The Biological Recording Company puts on a very wide range of webinars covering many different groups of species and issues related to wildlife, species identification and recording. They have a strong focus on invertebrates. Many are free or relatively low cost.
You can explore the range of things they offer by going to https://biologicalrecording.co.uk (check out the Entolearn and Entolive series of webinars) or signing up for their newsletter Biological Recording Company Newsletter Sign Up Form
You might also be interested in the Field Studies Council list of Natural History Courses for 2025 which are shown through this link:
https://www.field-studies-council.org/courses-and-experiences/natural-history-courses/
These cover a wide range of subjects, and include both online and in-person courses, some residential.
If you’d like to search for courses on a particular topic, you might find this link useful:
https://www.field-studies-council.org/fsc-natural-history-courses/
Courses are grouped in the broad subject areas of Fungi and lichens; Invertebrates; Plants; and Professional Environmental Field Skills, with further specialisms in each area.